I would see the show in passing and think, what the heck is this? It just looked so weird, and the animation is practically primitive compared to today's CG standards. But the concept is somewhat more complicated.

In the Foster's universe, imaginary friends become physical beings the instant a child imagines them. An Imaginary Friend is completely real and can be seen, heard, and felt by all under most circumstances. The only problem is that children outgrow them, and they're left to fend for themselves.